Search results for "Embryogenesi"
showing 10 items of 190 documents
Sequence of vascular patterning and gene transcription in the chick chorioallantoic membrane (15.1)
2014
Introduction: The chick chorioallantoic membrane (CAM) is a well-established model of both vasculogenesis and angiogenesis; however, little is known about the genetic control of vascular patterning in the CAM. Methods: Using recent advances in chicken genomics, we investigated the relative expression of 84 angiogenesis genes during the growth and remodeling of the CAM microcirculatory network. Chick embryos, cultured ex ovo, were studied during embryonic development days (EDD) 8-14. UV laser microdissection was used to harvest capillary plexus and 1st, 2nd, and 3rd order conducting vessels for qRT-PCR analysis. Results: Two transcription peaks were observed between EDD 8 and 14. The first p…
A factor derived from chick embryo retina which inhibits DNA synthesis of retina itself.
1992
Chick embryo retinas contain a peptide factor that inhibits DNA synthesis in explants of chick embryo retina. The inhibitory factor, obtained by acid/ethanol extraction from 15-day-old chick embryo retinas, was partially purified by affinity chromatography on heparin-sepharose CL-6B and gel filtration on Sephadex G-100. The inhibitor reduced DNA synthesis with maximal effects observed in retinal explants from 7 to 8-day-old chick embryos. The inhibitory effect became apparent after 10 h of incubation and reached the maximum levels after 16 h. DNA-inhibiting activity was heat and acid-stable and was destroyed by trypsin and alkaline treatments. The inhibitory effect was observed in retinal e…
Spatially restricted expression of PlOtp, a Paracentrotus lividus Orthopedia-related homeobox gene, is correlated with oral ectodermal patterning and…
1999
ABSTRACT Several homeobox genes are expressed in the sea urchin embryo but their roles in development have yet to be elucidated. Of particular interest are homologues of homeobox genes that in mouse and Drosophila are involved in patterning the developing central nervous system (CNS). Here, we report the cloning of an orthopedia (Otp)-related gene from Paracentrotus lividus, PlOtp. Otp is a single copy zygotic gene that presents a unique and highly restricted expression pattern. Transcripts were first detected at the mid-gastrula stage in two pairs of oral ectoderm cells located in a ventrolateral position, overlying primary mesenchyme cell (PMC) clusters. Increases in both transcript abund…
Rapid changes in heat-shock cognate 70 levels, heat-shock cognate phosphorylation state, heat-shock transcription factor, and metal transcription fac…
2010
The aim of the present study was to analyze and compare the effects of several metals on the embryos of the sea urchin Paracentrotus lividus, a key species within the Mediterranean Sea ecosystem. Embryos were continuously exposed from fertilization to the following metals: 0.6 mg/l copper, 3 mg/l lead, and 6 mg/l nickel. The embryos were then monitored for metal responses at the gastrula stage, which occurred 24 h after exposure. A biochemical multi-experimental approach was taken and involved the investigation of the levels of HSC70 expression and the involvement of heat shock factor (HSF) and/or metal transcription factor (MTF) in the response. Immunoblotting assays and electrophoretic mo…
Primary culture of single ectodermal precursors of Drosophila reveals a dorsoventral prepattern of intrinsic neurogenic and epidermogenic capabilitie…
1992
ABSTRACT We have analyzed the development in vitro of individual precursor cells from the presumptive truncal segmental ectoderm of the Drosophila embryo to study the intrinsic component in the determination of cell fate. For each cultured cell, the original position within as well as the developmental stage of the donor embryo were known. Cells removed from the ventral neurogenic region develop neural clones. Cells from the dorsal ectoderm and from the dorsalmost part of the ventral neurogenic ectoderm develop epidermal clones. These two classes of clones differ with respect to their division pattern, adhesiveness, cell morphologies and the expression of cell-specific markers. Mixed neural…
Fate-mapping in the procephalic region of the embryonic Drosopbila head
1994
Using intracellular horseradish peroxidase injection we traced the developmental fate of early gastrula cells of the procephalic region in the stage 16/17 embryo. Morphogenetic movements in the developing brain are described in three dimensions. The results are related to head segmentation, and an early gastrula fate map of pregnathal head segments is proposed.
Territorial localization of heat shock mRNA production in sea urchin gastrulae.
1985
In situ hybridization experiments with a labeled DNA probe indicate that the ability to respond to heat shock with the production of the mRNA for the 70 kd heat shock protein is segregated into the ectodermal cells already at the gastrula stage or earlier during the embryonic development of Paracentrotus lividus.
Hyperplastic Conotruncal Endocardial Cushions and Transposition of Great Arteries in Perlecan-Null Mice
2002
Perlecan is a heparan-sulfate proteoglycan abundantly expressed in pericellular matrices and basement membranes during development. Inactivation of the perlecan gene in mice is lethal at two developmental stages: around E10 and around birth. We report a high incidence of malformations of the cardiac outflow tract in perlecan-deficient embryos. Complete transposition of great arteries was diagnosed in 11 out of 15 late embryos studied (73%). Three of these 11 embryos also showed malformations of semilunar valves. Mesenchymal cells in the outflow tract were abnormally abundant in mutant embryos by E9.5, when the endocardial-mesenchymal transformation starts in wild-type embryos. At E10.5, mut…
Effects of tributyltin(IV) chloride exposure on early embryonic stages ofCiona intestinalis:In vivo and ultrastructural investigations
1993
The effects of tributyltin(IV) chloride (TBT chloride) solutions on ascidian embryos of Ciona intestinalis have been tested at different stages of development. It has been observed, in vivo, that TBT chooride inhibited cleavage of fertilized eggs and of embryo blastomeres giving rise to cellular masses that are not delimited by plasma membrane. Electron-dense precipitates of TBT chloride, probably as inorganic tin, have been observed by transmission electron microscopy in the egg cytoplasm of cellular masses. The same type of precipitate was present also inside the mitochondria, whose structure appeared to be highly modified. These ultrastructure aspects are indicative of a degenerative pro…
Myo-inositol counteracts the vegetalizing effect of lithium on P.lividus embryos
1992
Abstract The vegetalizing effect of LiCl on sea urchins embryos can be counteracted by the addition of myo-inositol. This observation is discussed in connection with similar results recently reported for amphibian embryos.